1. Field of the Invention
This invention relates to an internal combustion engine of the type including a plurality of cylinders split into first and second groups, the first group of cylinders held in operation independently of engine load conditions, and the second group of cylinders having no supply of fuel and fresh air so as to be placed out of operation when the engine is under low load conditions. The invention is more particularly concerned with an exhaust gas recirculation system for use with such a split engine for recirculation of a great amount of exhaust gases into the suspended cylinders while the engine is running under low load conditions.
2. Description of the Prior Art
Generally, there is a tendency of an internal combustion engine such that it consumes a smaller amount of fuel under a higher load condition. For the sake of high fuel economy under low load conditions, split engines have been deviced which run in a partial-cylinder mode of operation when they are under low load conditions. During this partial-cylinder mode of operation, some of the cylinders have no supply of fuel and fresh air and have their operation suspended so that the remainder of the cylinders can operate under resulting increased load conditions.
An exhaust gas recirculation system has been associated with such a split engine for recirculating a great amount of of exhaust gases into the suspended cylinders so as to reduce the pumping loss of the suspended cylinders which results in a greater fuel economy.
Conventional split engines are not very efficient and relatively high particularly while the engine is running under low load conditions. The conventional exhaust gas recirculation systems do not provide optimum performance of these engines.